Cerebrospinal Fluid Analysis in Patients with Post-neurosurgical Procedures: Meningitis vs. Non-meningitis

Cerebrospinal fluid (CSF) analysis is helpful in the diagnosis of infections of the central nervous system (CNS), especially after neurosurgical procedures. This study aimed to evaluate the diagnostic value of CSF markers for diagnosis of post-neurosurgical meningitis (PNM).

Patients with neurosurgical procedures whose CSF was obtained for any reason (meningitis and non-meningitis) during 2020 and 2022, at Imam Khomeini Hospital Complex, Tehran, Iran, were included. Serum and CSF lactate dehydrogenase (LDH), glucose, protein, white blood cells (WBC), red blood cells (RBC), and CSF/serum glucose and LDH ratio were compared between the patients who were diagnosed with PNM and those without meningitis.

A total of 115 patients were included, of whom 23 patients were diagnosed with PNM and 92 with non-meningitis. No significant differences were observed in patients' age, gender, and underlying diseases between the two groups. Findings showed a significantly (P=0.029) lower level of the mean CSF glucose (59.5 mg/dL ±33.9) in patients with meningitis than in patients without meningitis (76.8 mg/dL ± 37.5). The mean CSF/serum glucose ratio was 43.7% in the meningitis group and 56.3% in the non-meningitis group (P=0.008). The mean WBC count and neutrophil dominance were significantly higher in the meningitis group. No significant differences were observed in CSF LDH, Protein, and RBC between the two groups.

A CSF glucose level of less than 60 mg/dL, a CSF/serum glucose ratio of less than 0.44, and a higher CSF WBC and neutrophil count can help diagnose PNM.